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Hard starting 78 GS750

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    Hard starting 78 GS750

    Hello, I recently found a 78 GS750 that has a header and Kirker exhaust and a jet kit, also individual air filters installed. The bike runs great when it is warm, in fact it really screams, great throttle response and runs very smooth through the rev range. My problem is that it is very hard to start when cold. I did a full tune-up, replaced the coils and it still acts the same with the old points, condensers, plugs and coils. Would the fact that it has been re-jetted and a header installed require a hotter plug? I'm not a mechanic, but am capable of doing routine maintainence and tune-ups. All of my bikes in the past have been pretty much stock, so this is a bit new to me. Thr carbs were supposed to have been cleaned and synched by a qualified mechanic this spring. Any help at all would be greatly appreciated.

    #2
    If the bike runs fine then warm, I would check if the choke works as is should.

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      #3
      clod starting

      I have the same problem with my stock 78 gs1000 , One of the guys in the gsresources suggested turning the petcock to prime for 20 or so seconds then turn it back to run...................it works for me...........even with a old battery. 8)

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        #4
        How's the idle speed? This past summer I bought a low mileage '78 GS750E from a distant Suzuki dealer. They claimed to have cleaned the carbs, too. Ran fine warm, I rode it home from the dealership (90 miles) with no problem, except idle speed was erratic, usually ~ 2000rpm, but sometimes 1500, sometimes something else. Once at home, I found cold starting and warmup to be difficult, too. Felt the pipes, found I generally had one hot pipe, one warm pipe, and 2 cool ones. :? Conclusion: carbs still need work. :x Took them apart and found that whatever had been done, a proper carb cleaning was not included. I found lots of varnish and deposits; 3 of the 4 carbs had a clogged passage. :roll: I still have them apart; haven't had the time to spend finishing the job, but there's no doubt what the problem was. Looking forward to getting things back together!

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          #5
          Re: Hard starting 78 GS750

          Originally posted by cjsw
          Hello, I recently found a 78 GS750 that has a header and Kirker exhaust and a jet kit, also individual air filters installed. The bike runs great when it is warm, in fact it really screams, great throttle response and runs very smooth through the rev range. My problem is that it is very hard to start when cold. I did a full tune-up, replaced the coils and it still acts the same with the old points, condensers, plugs and coils. Would the fact that it has been re-jetted and a header installed require a hotter plug? I'm not a mechanic, but am capable of doing routine maintainence and tune-ups. All of my bikes in the past have been pretty much stock, so this is a bit new to me. Thr carbs were supposed to have been cleaned and synched by a qualified mechanic this spring. Any help at all would be greatly appreciated.
          Thanks to all who replied. I think I'll probably just go ahead and tear them down myself. I think maybe they were not cleaned well before, if at all. I'll probably get to them in the next couple of weeks. I love this bike. It has a wonderful sound with the header and Kirker exhaust. Not real loud, just very nice, especially when you get up in the revs a bit. Thanks again for the input.

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            #6
            The choke tube comes down from the carb body and draws fuel from the hole in the carb bowl bottom. It is critical that these flow fuel: if not, the choke circuit doesn't work.

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